Abstract: The large-depth, multi-function electromagnetic survey system is composed of the multi-function electromagnetic detection equipment, the techniques for data acquisition and processing and the software for electromagnetic two or three dimensional positive inversion simulation. Based on a study of its corresponding key technologies, a distributed multi-function receiver prototype is developed. Accordingly, the high-power multi-function intelligent transmitting prototype and the three component high temperature superconducting magnetic sensor are also designed and developed. As a result, the matched data acquisition, processing, and interpreting technology of the multi-function electromagnetic system have been successfully resolved. The system has the measurement function of AMT, MT, CSAMT and IP. A number of good results have achieved in comparative trail between the self-developed system and the GDP-32^Ⅱsystem, and the application of typical mine areas.